Abstract The kinetics of the reaction of H‐atom with carbonyl sulfide (OCS) has been investigated at nearly 2 Torr total pressure of helium over a wide temperature range, T = 255–960 K, using a low‐pressure discharge flow reactor combined with an electron impact ionization quadrupole mass spectrometer. The rate constant of the reaction H + OCS → SH + CO (1) was determined under pseudo‐first order conditions, monitoring the kinetics of H‐atom consumption in excess of OCS, k 1 = 6.6 × 10 −13 × ( T /298) 3 × exp(−1150/ T ) cm 3 molecule −1 s −1 (with estimated total uncertainty on k 1 of 15% at all temperatures). Current measurements of k 1 at intermediate temperatures (520–960 K) appear to reconcile previous high and low temperature data and allow the above expression for k 1 to be recommended for use in the extended temperature range between 255 and 1830 K with a conservative uncertainty of 20%.